X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=doc%2Fguides%2Fprog_guide%2Fmetrics_lib.rst;h=eca855d60185f57a8468ad990788e65f9ce13c12;hb=0b133c36ad7d5fdce852b060d69019d69d48a7cb;hp=5cbe17c9037a41ef62c8b67bf0fa8b2da61ce4b7;hpb=5630257fcc30397e7217139ec55da4f301f59fb7;p=dpdk.git

diff --git a/doc/guides/prog_guide/metrics_lib.rst b/doc/guides/prog_guide/metrics_lib.rst
index 5cbe17c903..eca855d601 100644
--- a/doc/guides/prog_guide/metrics_lib.rst
+++ b/doc/guides/prog_guide/metrics_lib.rst
@@ -25,7 +25,7 @@ individual device. Since the metrics library is self-contained, the only
 restriction on port numbers is that they are less than ``RTE_MAX_ETHPORTS``
 - there is no requirement for the ports to actually exist.
 
-Initialising the library
+Initializing the library
 ------------------------
 
 Before the library can be used, it has to be initialized by calling
@@ -154,6 +154,20 @@ print out all metrics for a given port:
     }
 
 
+Deinitialising the library
+--------------------------
+
+Once the library usage is done, it must be deinitialized by calling
+``rte_metrics_deinit()`` which will free the shared memory reserved
+during initialization.
+
+.. code-block:: c
+
+    err = rte_metrics_deinit(void);
+
+If the return value is negative, it means deinitialization failed.
+This function **must** be called from a primary process.
+
 Bit-rate statistics library
 ---------------------------
 
@@ -271,3 +285,12 @@ de-initialise the latency library.
 .. code-block:: c
 
     rte_latencystats_uninit();
+
+Timestamp and latency calculation
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The Latency stats library marks the time in the timestamp field of the
+mbuf for the ingress packets and sets the ``PKT_RX_TIMESTAMP`` flag of
+``ol_flags`` for the mbuf to indicate the marked time as a valid one.
+At the egress, the mbufs with the flag set are considered having valid
+timestamp and are used for the latency calculation.